Control device



July 27, 1937. E. J. DILLMAN CONTROL DEVICE Original Filed Dec 12, 19:50

I: :1 Fisi Fis. 5

Iillll li ll INVENTOR h ATTORNEY Patented July 27, 1937 UNITED STATES CONTROL DEVICE Earnest J. Dillman, Detroit, Mich, assignor to Detroit Lubricator Company, Detroit, Mich, a corporation of Michigan Original application December 12, 1930, Serial No. 501,927. Patent No. 1,992,155, dated February 19, 1935. Divided and this application July 27, 1934, Serial No. 737,288

Claims.

My invention relates to new and useful improvements in control devices, and more particularly to a device for automatically controlling a motor means, such, for example, as the fan motor of a 5 unit heater system.

An object of my invention is to provide a control means which is automatically movable between predetermined limits, and which has means operable thereon in response to a predetermined condition to maintain the control means at one limit of movement.

Another object is to provide a control means which is normally operable between limits by automatic means in response to predetermined conditions, and which has means operable in re sponse to a predetermined condition to move the control means toward one of its limits irrespective of operation of the automatic means.

Another object is to provide a control means for a uni heater which is normally operable to control the unit heater fan means, and having means responsive to the unit heater temperature and operable on the control means to prevent control thereby of the fan means.

2 The invention consists in the improved construction and combination of parts, to be more fully described hereinafter, and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawing, to be taken as a part of this specification, I have fully and clearly illustrated a preferred embodiment of my invention, in which drawing Figure 1 is a view in front elevation of a unit heater showing my control device applied thereto;

Fig. 2 is an enlarged detail View, partly in section, looking from right to left of Fig. 1 and showing the control device;

Fig. 3 is a detail view on the line 3--3 of Fig. 2, and

Fig. 4 is a detail view on the line 4-4 of Fig. 2.

Referring to the drawing by characters of reference, I designates generally the casing of a unit heater, preferably having its underside or bottom open to provide an inlet for circulation of air through the casing and having conduit or duct members 2 communicating with the interior of the casing and supported on the top casing wall to provide air outlets. Within the casing are air circulating means 3, preferably rotary fans of the squirrel cage type which draw air in through the open bottom of the casing and discharge the air through the members 2, and which are mounted on a drive shaft 4 journaled in the end or side walls of the casing. Also within the casing below the fan means is a heat trans-fer element 5 for varying the sensible heat of the air flowing through the casing, and which is preferably a heating means such as a radiator or the like having a conduit for conveying a heating medium such as steam thereto and condensate and steam therefrom. The conduit comprises an inlet pipe 6 and an outlet pipe I, which pipes extend through the casing walls, preferably at the ends thereof, beneath the shaft 4. Fixed to the end wall 8 external of the casing, is a supporting bracket or member 9 on which is mounted a fan driving means I0, preferably an electric motor, which is connected to the end of shaft 4 which projects through wall 8. Secured to wall 8 external of the casing and below the element 5, is. my control device I I which controls the motor I II and therefore the operation of the fan means 3.

The device II comprises a control means I2, preferably an electric switch of the mercury tube type, in which a globule of mercury enclosed in a sealed glass tube is operable to make and break contact, upon tilting or rocking of the tube, with terminals which extend into the tube. The means I2 is carried by a clip member I3 fixed to a carrier member I4 having downward extending end flanges I5, I6. Extending through the flanges I5, I6 is a pin or shaft IT on which the means I2 is fulcrumed for rocking or tilting movement between predetermined limits. The shaft IT is secured, as at I8, in the rear wall I9 of a casing or housing 20 which encloses the means I2. Within casing 20 is a vertically movable lever means 2| fulcrumed at one end in the end casing wall 22 and terminating at its free end beneath the shaft H in a substantially vertical, laterally extending portion 23 (Fig. 4) having a nut member 24 secured thereto and through which and the portion 23 is adjustably threaded a screw member 25 having a conical end 26. Projecting from the other casing end wall 21 is a supporting abutment 28 between which and the screw end 26 is a resilient means 29, preferably a coil spring, held under compression. Bearing at one end against the casing top wall 30 is a resilient means 3 I, preferably a coil spring, held under compression and bearing at its lower end against the top face of lever means 2|. The spring means 29 and 3| which are adjustable, act conjointly to resist upward movement of the lever means and to deterr.- 1e the upward force required to lift the lever means 2I and serve on decrease of the lever lifting force to move the lever means 2I downward. The lifting force for the lever means 2| is provided by a power element 32 which is secured to the underside of the casing bottom wall 33 and which has a reciprocable plunger 34 extending upward through wall 33 into engagement with the underside of lever means 2| directly beneath the" spring means 3|. The element 32 preferably comprises a hermetically sealed bulb or container having a resilient wall to which the lower end of plunger 34 is connected, and containing a charge of volatile liquid, such that element 32 is a temperature responsive means or thermostat responsive to the temperature of the air outside of the casing I. The element 32 and spring means 29, 3| comprise an automatic operating means for the switch tube l2. In line with the element 32 the heater casing end wall 8 is provided with an inlet aperture 35 so that the element 32 is directly responsive to the temperature of the air being drawn into the casing l, which air has circulated through the space to be .heated. The carrier member flangelli has an operating arm 36 which extends substantially directly over and above the ,Xree end of lever portion 23. Pivoted to and depending Irom arm 36 is a link or rod member 31 having its lower end slotted, as at 38. The free end of portion 23 is reduced to provide a pin member 39 which extends into the slot 38. Below the slot 38 the link 31 has an aperture 48 which receives one end of a spring member 4| which is wound about nut member 24 and has its other end secured to lever portion 23 such that the spring member 4| normally tends to pull the link 31 downward and the upper end of slot 38 into engagement with pin 39. Mounted rigidly on the top wall 38 is a power element 42 comprising an hermetically sealed container 43 having a resilient wall 44 to which is secured a plunger 45 which extends downward through an aperture in the top wall 38 substantially over the shaft |1. Positioned between the resilient wall 44 and the casing wall 38 is a coil spring 46 which surrounds plunger 45 and normally tends to move the same upwardly and to maintain the same in a raised position. Secured rigidly on the free end of plunger 45 within the casing 20, is a holding means 41, preferably a hook member, which extends downward adjacent to and slightly below a side edge of the carrier member M to the rear of arm 38, and has a substantially horizontal arm 48 projecting beneath the carrier member |4 between arm 38 and means |2. The member M has secured thereto, between arm 36 and means l2, an angle plate member 49 with a depending flange 50 which cooperates with and is engageable by the hook arm 48. The top or end wall 5| of container 43 has secured thereto and opening therethrough, one end of a tube 52 which is sealed at its free end, as at 53, and which is wrapped or coiled about the outlet pipe 1 in heat conducting relation thereto. The tube 52 and container 43 are charged with a volatile liquid so that the element 42 and tube 52 comprise a temperature responsive means or thermostat. One terminal of the motor |8 preferably connects directly to an electric main or supply line by a lead 54, while the other lead 55 from the supply line connects to one terminal of the control means l2. The remaining terminal of the motor l0 and the other terminal of means l2 are connected together by a lead 56, so that the motor I0 is in series circuit with the control means l2.

The operation of my device as embodied in a unit heater system, is as follows: When the element 5 has been heated by steam or other heating medium supplied by pipe 6, the outlet pipe 1 will have its temperature raised. When the temperature of element 5 has been raised to a predetermined degree at which the temperature of the outlet pipe 1 will be at, say, about 160 F., then the volatile liquid in the coiled tube or bulb 52 will have expanded, exerting sufficient pressure to overcome the resistance of spring 48 and move the holding means 41 downward. As the hook arm 48 of means 41 is moved downward, the light spring 4| acting through link 31 will tilt or rock the control means or switch tube |2 clockwise of Fig. 2 on its fulcrum l1 to make contact between leads 55, 56 and start the fan motor l0. Downward movement of link 31 is permitted by the pin and slot connection between the link 31 and lever 2|, and when arm 48 is completely depressed by the power means 42, the upper end of slot 38 will be in engagement with pin 39 and be so held by spring 4|. Operation of motor I0 will drive fan means 3 to draw air from the space to be heated in through the bottom of casing I, over or in contact with the heater element 5 and discharge the heated air through. the ducts 2. The fan means 3 will also draw air into the casing through the inlet aperture 35 which air will flow over the power means 32. When the temperature of the air passing over means 32 has been raised by the heated air dischargedirom ducts 2 to a predetermined degree-say, F., then the pressure of the volatile liquid in means 32 will have built up sufficiently to overcome the resisting force of springs 29 and 3| and will move lever means 2| upward. As lever means 2| moves upward, the pin 38 which is in engagement with the upper end of slot 38 will lift the link 31 and tilt or rock the switch tube or control means |2 counter-clockwise to the position of Fig. 2 to break the circuit of fan motor l0 and stop the further discharge thereby of heated air through ducts 2. Should the temperature of the air surrounding casing now fall to, say, 68 F., the pressure within means 32 will have decreased sufficiently to permit springs 29 and 3| to move lever means 2| downward, which movement will be transmitted to link 31 by spring 4| and tilt the switch tube l2 to make contact and again start the fan motor I0. If during the operation of the fan motor ID the temperature of the heater element 5 decreases below the desired temperature so that the temperature of outlet pipe 1 becomes less than the predetermined temperature of 160 F., then the spring 46 will act upon reduction of pressure in container 43 and tube 52 to raise the hook member 41. As member 41 moves upward, arm 48 will engage flange 50 and tilt the switch tube |2 to the position of Fig. 2, thus breaking the fan motor circuit and will hold or maintain the means |2 in circuit breaking position, irrespective of operation of lever means 2 The up ward force of spring 46 acting on means 41 to tilt the means l2 to circuit breaking position, need only be sufficient to overcome the light spring 4|, as the springs 29 and 30 do not resist upward movement of means 41 by reason of the pin and slot, or lost motion connection between link 31 and lever means 2|.

Although I have shown and described my control device as embodied in a unit heater system, it is to be noted that the same is capable of use in other systems wherein it is desired to control a motor means in response to variations of temperature or pressure, and to prevent operation of application Serial No. 501,927 filed December 12, 1930, now Patent 1,992,155, Feb. 19, 1935.

What I claim and desire to secure by Letters Patent of the United States is:

1. A device of the character described,. comprising a casing, switch means in said casing, automatically operable power means for actuating said switch means, means interconnecting said power means and said switch means, spring means urging said switch means to circuit breaking position, said connecting means including a lost-motion connection whereby to permit operation of said switch means by said Spring means,

and automatically acting responsive means operable to overcome said spring means whereby to permit operation of said switch means by said power means.

2. A device of the character described, comprising a casing, switch means in said casing, automatically operable power means for actuating said switch means, means interconnecting said power means and said switch means, a helical coil spring under compression and acting upon expansion to move said switch means to circuit breaking position, said connecting means including a lost-motion connection whereby to permit operation of said switch means by said spring means, and automatically acting responsive means operable to compress said spring means whereby to permit operation of said switch means by said power means.

3. A control device of the character described, comprising a carrier member having a fulcrum support, a switch tube supported by said member and tiltable about said support, automatic means operable to tilt said tube to make and break circuit, means operable to engage said carrier member to tilt said tube, and a resilient connection operatively connecting said automatic means and said member and yieldable whereby said last-named means may tilt said tube in opposition to said automatic means.

4. A control device of the character described, comprising a carrier member having a fulcrum support, a switch tube supported by said member and tiltable about said support, automatic means operable to tilt said tube to make and break circuit, a hook member operable to engage said carrier member to tilt said tube and having means normally acting thereon to tilt said tube, and temperature responsive means operable to overcome said last-named means to permit operation of said tube by said automatic means.

5. A control device of the character described comprising a movable switch for controlling an electric circuit, means operable to move said switch to make and break circuit, means operable to move said switch to and hold said switch in a predetermined circuit controlling position, a lostmotion connecting member connecting said firstnamed means and said second-named means so that said second-named means can move said switch to said predetermined position irrespective of the operation of said first-named means, means operable to overcome said second-named means, and resilient means operatively connecting said first-named means and said switch for transmitting movement from said first-named means to said switch, said resilient means being held under tension by said second-named means when said switch is held in said predetermined position and having a force stored therein operable to move said switch to another position upon the overcoming of said second-named means.

6. A control device of the character described comprising switch means, automatically operable power means for actuating said switch means, spring means urging said switch means to circuit breaking position, means connecting said power means and said switch means, said connecting means including a lost-motion connection where-v by to permit operation of said switch means by said spring means, an automatically acting responsive means operable to overcome said spring means to permit operation of said switch means by said power means, and spring means operatively connectingsaid switch means and said power means, said last-named spring means being held under tension by said first-named spring means when the switch means is in circuit opening position and having a force stored therein operable to move said switch means to circuit closing position upon the overcoming of said firstnamed spring means.

'7. In a device of the character described, a supporting means, a movable switch means supported by said supporting means, automatically operable power means for actuating said switch means, yieldable means operable to directly act on and move said switch means to and maintain said switch means in a predetermined position, means operable to overcome said yieldable means, and yieldable means operatively connecting said power means and said switch means and yieldable so that said first-named yieldable means is operable to move said switch to said predetermined position irrespective of the operation of said power means, said last-named yieldable means being held under tension by said first-named yieldable means when said switch means is maintained in said predetermined position and having a force stored therein operable to move said switch means to another position upon the overcoming of said first-named yieldable means.

8. In a device of the character described, a casing, switch means movably supported in said casing, a lever member fulcrumed in said casing and having a pin, a power element for operating said lever member, a connecting link connecting said lever member and said switch means, said link having a slot for receiving the pin of said lever member to provide a lost-motion connection between said link and said lever member, a spring means acting to maintain operative connection between said lever member and said link, yieldable means operable to move said switch means to a circuit opening position without transmission of said movement to said lever member, said yieldable means placing said spring means under tension exerting a force tending to move said switch means to circuit closing position, and automatically operable power means operable to overcome said yieldable means to release the force of said spring means for moving said switch means to closed circuit position and to permit operation of said switch means by said firstnamed power means.

9-. A control device of the character described comprising a movable controlling means, movable holding means operable to hold said controlling means in one position and movable so that said controlling means can move to another position, power means for moving said holding means, power means operable to move said controlling means, lost motion connecting means operatively connecting said second-named power means and said controlling means, and spring means acting through said lost motion connecting means to move said controlling means and held inactive by in said one position, lost motion connecting means operatively connecting said second-named power means and said controlling means, and spring means operable on movement of said holding means out of holding relation with said controlling means to move said controlling means to another position, said spring means acting on said controlling means through said lost motion connecting means and operable to establish positive connection between said second-named power 10 means and said controlling means.

EARNEST J. DILLMAN. 

